1. Field of the Invention
The present invention relates to a printing system which controls timeout processing of a network-connected printing apparatus.
2. Description of the Related Art
Recently, Windows 7® OS (Operating System) available from Microsoft, USA adopts WSD (Web Service on Device) as a method for printing by a network-connected printing apparatus. Detailed information of WSD is laid open to the public in “Windows Hardware Developer Central” by Microsoft Corporation [online] [searched on Oct. 11, 2010] on the Internet (URL: http://www.microsoft.com/whdc/connect/rally/rallywsd.mspx). To avoid occupying a network-connected printing apparatus when printing by a network-connected printing apparatus, there has conventionally been proposed a technique of releasing occupation of the printing apparatus by performing timeout processing unless an information processing apparatus which has transmitted a print job accesses the printing apparatus for a predetermined period.
There is also disclosed processing in which a printing apparatus analyzes a print start request, if no error has occurred, creates a port, and if the port has not been accessed for a predetermined period, closes the port (see Japanese Patent Laid-Open No. 2004-341734).
For example, in manual printing, transmission of print data to a printing apparatus may intentionally stop so that the printer driver can display a manual printing guide dialog. Even in this case, there is a technique of preventing generation of a timeout error by periodically inquiring status information of a printing apparatus.
As a general OS print support function, there is a method of, when a network cable connected to an information processing apparatus is plugged out and plugged in, deleting a print job during printing and newly printing again a job of the same contents. For example, when the network cable is plugged out and plugged in during printing of job 1, the print support function deletes job 1 held in the print queue, and newly generates and prints a job of the same contents as job 2.
At this time, the printing apparatus cannot detect the plug-out and plug-in of the network cable connected to the information processing apparatus, and keeps processing job 1. The port monitor of the information processing apparatus issues a job 2 print start request to the printing apparatus. However, the printing apparatus is processing job 1 and thus sends back an error response. The language monitor of the information processing apparatus issues a status acquisition request to the printing apparatus. Because of access from the information processing apparatus, the printing apparatus resets the timeout processing counter. As a result, no timeout occurs, and the printing apparatus keeps processing job 1 and cannot start processing of job 2 for a predetermined period.